基于光谱空间密度分析的边缘提取

针对传统的边缘提取方法大部分不适应高光谱数据的特点，提出了基于光谱空间密度分析边缘提取的思想。在分组主分量变换提取第一主分量作为特征维的基础上，采用面向对象的二次判别边缘的方法，通过立体判决将光谱空间中低密度超椭球体集群视为真实边缘点集群。试验表明，此方法是合理可行的。     

基于GPS掩星技术反演大气参数模型的优化

准确掌握地球大气中的水气分布，了解水气变化趋势对天气现象、全球气候变化、数值预报具有理论研究及实用价值。以无线电掩星技术为基础，利用掩星数据反演大气参数剖面。对原反演模型的不足进行了论证，并给出了反演个例。详细地论述了通过引入MM5先验温度T再通过线性迭代的方法反演对流层下部水汽廓线原理，给出了优化后模型反演个例。并对模型优化后反演廓线中存在的问题进行了分析，提出了下一步优化方向。     

福州市土地利用景观格局分析

以福州市土地利用现状图为基本图件，在GIS支持下编制了福州市土地利用景现图，进而选取几种主要指数，通过Excel软件计算，定量分析了福州市土地利用的景观格局及破碎化特征。结果表明：林地为基质景观，优势度指数最高，分离度指数最低；耕地、园地、城镇村及工矿用地和水域的均匀度较高，多样性指数较大，但破碎化程度较深；未利用地破碎度最低。从总体上看，土地利用的景观比较单调、多样性指数较小、破碎化程度也较低，景观异质性不高。     

彝族撒尼人原始宗教中的生态伦理观--以石林圭山海宜老寨为例

人类的生存和发展离不开自然生态环境。当今,由于人为的原因,生态危机已成为全球性的环境问题。环境保护迫在眉睫。而一些原住民族却拥有一套颇为有效的环境保护知识体系。作为传统生态伦理主要载体的神山森林,在石林圭山海宜老寨的环境保护中起着重要作用。从生态人类学的视角出发,初步探讨了彝族撒尼人原始宗教中的生态伦理观,展现了撒尼人原始宗教中所包含的丰富的环境价值观念,揭示了撒尼人生态环境保护的奥秘。     

Clinoform growth and sediment flux into late Cenozoic Qiongdongnan shelf margin,South China Sea

The South China Sea continental margin in the Qiongdongnan Basin (QDNB) area has incrementally prograded since 10.5 Ma generating a margin sediment prism more than 4km-thick and 150–200 km wide above the well-dated T40 stratigraphic surface. Core and well log data, as well as clinoform morphology and growth patterns along 28 2D seismic reflection lines, illustrate the evolving architecture and margin morphology; through five main seismic-stratigraphic surfaces (T40, T30, T27, T20 and T0) frame 15 clinothems in the southwest that reduce over some 200 km to 8 clinoforms in the northeast. The overall margin geometry shows a remarkable change from sigmoidal, strongly progradational and aggradational in the west to weakly progradational in the east. Vertical sediment accumulation rate increased significantly across the entire margin after 2.4 Ma, with a marked increase in mud content in the succession. Furthermore, an estimate of sediment flux across successive clinoforms on each of the three selected seismic cross sections indicate an overall decrease in sediment discharge west to east, away from the Red River depocenter, as well as a decrease in the percentage of total discharge crossing the shelf break in this same direction. The QDNB Late Cenozoic continental margin growth, with its overall increased sediment flux, responded to the climate-induced, gradual cooling and falling global sea level during this icehouse period.     

Dynamic response of a pile considering the interaction of pile variable cross section with the surrounding layered soil

Assuming that the pile variable cross section interacts with the surrounding soil in the same way as the pile toe does with the bearing stratus, the interaction of pile variable cross section with the surrounding soil is represented by a Voigt model, which consists of a spring and a damper connected in parallel, and the spring constant and damper coefficient are derived. Thus, a more rigid pile–soil interaction model is proposed. The surrounding soil layers are modeled as axisymmetric continuum in which its vertical displacements are taken into account and the pile is assumed to be a Rayleigh–Love rod with material damping. Allowing for soil properties and pile defects, the pile–soil system is divided into several layers. By means of Laplace transform, the governing equations of soil layers are solved in frequency domain, and a new relationship linking the impedance functions at the variable‐section interface between the adjacent pile segments is derived using a Heaviside step function, which is called amended impedance function transfer method. On this basis, the impedance function at pile top is derived by amended impedance function transfer method proposed in this paper. Then, the velocity response at pile top can be obtained by means of inverse Fourier transform and convolution theorem. The effects of pile–soil system parameters are studied, and some conclusions are proposed. Then, an engineering example is given to confirm the rationality of the solution proposed in this paper. Copyright © 2017 John Wiley & Sons, Ltd.     

Water mining from the deep critical zone by apple trees growing on loess

There have been significant recent advances in understanding the ecohydrology of deep soil. However, the links between root development and water usage in the deep critical zone remains poorly understood. To clarify the interaction between water use and root development in deep soil, we investigated soil water and root profiles beyond maximum rooting depth in five apple orchards planted on farmland with stand ages of 8, 11, 15, 18, and 22 years in a subhumid region on the Chinese Loess Plateau. Apple trees rooted progressively deeper for water with increasing stand age and reached 23.2 ± 0.8 m for the 22‐year‐old trees. Soil water deficit in deep soil increased with tree age and was 1,530 ± 43 mm for a stand age of 22 years. Measured root deepening rate was far great than the reported pore water velocity, which demonstrated that trees are mining resident old water. The deficits are not replenished during the life‐span of the orchard, showing a one‐way mining of the critical zone water. The one‐way root water mining may have changed the fine root profile from an exponential pattern in the 8‐year‐old orchard to a relative uniform distribution in older orchards. Our findings enhance our understanding of water‐root interaction in deep soil and reveal the unintended consequences of critical zone dewatering during the lifespan of apple trees.     

Generation of continuous surface soil moisture dataset using combined optical and thermal infrared images

Surface soil moisture (SSM) is a critical variable for understanding water and energy flux between the atmosphere and the Earth's surface. An easy to apply algorithm for deriving SSM time series that primarily uses temporal parameters derived from simulated and in situ datasets has recently been reported. This algorithm must be assessed for different biophysical and atmospheric conditions by using actual geostationary satellite images. In this study, two currently available coarse‐scale SSM datasets (microwave and reanalysis product) and aggregated in situ SSM measurements were implemented to calibrate the time‐invariable coefficients of the SSM retrieval algorithm for conditions in which conventional observations are rare. These coefficients were subsequently used to obtain SSM time series directly from Meteosat Second Generation (MSG) images over the study area of a well‐organized soil moisture network named REMEDHUS in Spain. The results show a high degree of consistency between the estimated and actual SSM time series values when using the three SSM dataset‐calibrated time‐invariable coefficients to retrieve SSM, with coefficients of determination (R²) varying from 0.304 to 0.534 and root mean square errors ranging from 0.020 m³/m³ to 0.029 m³/m³. Further evaluation with different land use types results in acceptable debiased root mean square errors between 0.021 m³/m³ and 0.048 m³/m³ when comparing the estimated MSG pixel‐scale SSM with in situ measurements. These results indicate that the investigated method is practical for deriving time‐invariable coefficients when using publicly accessed coarse‐scale SSM datasets, which is beneficial for generating continuous SSM dataset at the MSG pixel scale.     

Is the interdecadal variation of the summer rainfall over eastern China associated with SST?

The present study examined the major features of the interdecadal variation of the summer rainfall over eastern China (IVRC) and the possible association with sea surface temperature (SST). We noted that the first leading mode of IVRC (accounting for nearly half of the total variance and with maximum loading for the summer rainfall anomalies over South China) may be not forced by SST. On the other hand, the second and third leading modes [accounting for 17.1 and 13.6 % of the total variance and mainly associated with the summer rainfall anomalies over the Yangtze River valley (YRV) and North China, respectively] in some extent are forced by SST anomalies. These observational results are confirmed by atmospheric general circulation model (AGCM) simulations forced by observed SST. By eliminating the internal dynamical process driven rainfall though ensemble mean, the simulations further suggest an overall enhancement of the intensity of IVRC in the corresponding ensemble mean, especially in the YRV and North China regions, but not in South China. That implies the different role of SST in driving IVRC over different regions.     

一次东北冷涡暴雨过程成因分析

利用常规气象观测资料、NCEP 1°×1°逐6h的再分析资料和FY-2E红外云图、TBB等资料,对2014年7月7—8日由东北冷涡引发内蒙古东北部的暴雨过程形成原因进行了天气学诊断分析,结果表明:1低空急流是主要水汽来源,不同地区出现暴雨的机制不同,兴安盟东部、呼伦贝尔市东南部由于槽前、切变南缘地面暖锋附近,中低空急流汇合处,强辐合抬升触发不稳定能量释放导致强天气的发生,而呼伦贝尔市西南部暴雨跟中上层冷涡的生成发展与对应的地面低压逐步耦合的动力作用相关;2湿位涡的分布对暴雨的发生、落区有较强的指示性作用,700hPa正负值区过度带的配置是暴雨发生发展的有利潜势,暴雨发生在700hPa等值线密集带和850hPa MPV2大于等于0的叠加区域内,700hPa正负过渡带附近,偏向于正值一侧;3最大降水量的雨强落后于云团TBB最低值1~2h,并不是强TBB与最强降水同步出现。